Side seal mechanism for rotary piston engine

ABSTRACT

A side seal mechanism for use in an annular or arcuate side seal groove which is formed in a side surface of a rotor rotatably received within an engine housing of a rotary piston engine. The side seal mechanism has an annular or arcuate side seal member sized and shaped to be slidably received in the side seal groove of the rotor with its axially outer end slidably contacting an axially inner side wall of the engine housing to provide an oilor gas- tight seal. The side seal mechanism defines at least one guide groove in at least either of the bottom wall of the annular or arcuate side seal groove and the bottom wall of the annular of arcuate side seal member, and a generally annular or arcuate wire spring fittedly received in the guide groove for biasing the side seal member toward the inner side wall of the engine housing. The wire spring is formed with several alternate axial projections which are positioned in a coaxial cylinder or in an arcuate strip both common to the guide groove.

United States Patent [191 Uchiyama SIDE SEAL MECHANISM FOR ROTARY PISTON ENGINE [75] Inventor: Yoshio Uchiyama, Noriyuki Kurio,

t hea ta o [73] Assignee: Toyo Kogyo Co., Ltd., Aki-gun,

Hiroshima-ken, Japan [22] Filed: May 8, 1973 [21] Appl. No.: 358,269

Hamada 418/61 A 1451 Feb. 18,1975

FOREIGN PATENTS OR APPLICATIONS 763,282 2/1934 France 277/161 Primary Examiner-John J. Vrablik Attorney, Agent, or Firm-Fleit & Jacobson [5 7] ABSTRACT A side seal mechanism for use in an annular or arcuate side seal groove which is formed in a side surface of a rotor rotatably received within an engine housing of a rotary piston engine. The side seal mechanism has an annular or arcuate side seal member sized and shaped to be slidably received in the side seal groove of the rotor with its axially outer end slidably contacting an axially inner side wall of the engine housing to provide an oilor gastight seal. The side seal mechanism defines at least one guide groove in at least either of the bottom wall of the annular or arcuate side seal groove and the bottom wall of the annular of arcuate side seal member, and a generally annular or arcuate wire spring fittedly received in the guide groove for biasing the side seal member toward the inner side wall of the engine housing. The wire spring is formed with several alternate axial projections which are positioned in a coaxial cylinder or in an arcuate strip both common to the guide groove.

9 Claims, 12 Drawing Figures PATENTED FEB I 8 I975 SHEET 1 [IF 2 FIG.3

F l G, l PRIOR ART FIG.4

F I G. 2 PRIOR ART SIDE SEAL MECHANISM FOR ROTARY PISTON ENGINE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in a side seal mechanism for use in a rotor of a rotary piston engine, and, more particularly, to improvements in a biasing element used in the side seal mechanism for biasing the side seal member toward the side wall of the engine housing.

2. Description of the Prior Art Previously, several types of springs have been used as a biasing element which acts to bias a side seal member toward a side wall of a housing of a rotary piston engine. One of the most popular types is a corrugated leaf spring which is necessarily required to have an annular or arcuate configuration with its corrugations being arranged in the axial direction ofa rotor of the rotary piston engine. As is well known in the prior art, such configuration will invite difficulties in its increased manufacturing steps. In order to obviate this drawback, another type of spring has been developed which is in the form ofa wire spring. This wire spring is also of annular or arcuate configuration, and is formed with a plurality of alternate projections not only in the axial direction but also in the radial direction with respect to the rotor. The wire spring has a reduced production cost, but is accompanied by a drawback of reduced mechanical strength due to torsion, which will be discussed in more detail with reference to the drawings.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide an improved side seal mechanism for use in an annular or arcuate side seal groove which is formed in a side surface of a rotor of a rotary piston engine.

Another object of the present invention is to provide an improved side seal mechanism which has sufficient mechanical strength to torsional attack with as reduced production cost.

According to a major aspect of the present invention, the wire spring as used as a biasing element is formed with a plurality of alternate projections which are positioned in a coaxial cylinder or in an arcuate strip both common to the guide groove of the rotor, that is to say, only in the axial direction with respect to the rotor, so that the wire spring is free from breakage due to the torsional attack or concentration of stress.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a top plan view showing a conventional wire spring as used in a side seal mechanism;

FIG. 2 is a cross-sectional view taken along the line 2 2 of FIG. 1; when the wire spring is used in a side seal mechanism.

FIG. 3 is a top plan view showing a wire spring used in a side seal mechanism according to the present invention;

FIG. 4 is a side clevational view showing the wire spring of FIG. 3;

FIG. 5 is a side elevational view showing another embodiment of the wire spring;

FIGS. 6 to 10 are cross-sectional views showing several arrangements of the wire springs of FIGS. 4 and 5 in the side seal mechanism of the present invention;

FIG. 11 is a side elevational view showing a rotary piston engine in which the side seal mechansim of the invention is used; and

FIG. 12 is a cross-sectional view taken along the line 12 -12 of FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2, a conventional :side seal mechanism designated by reference numeral 20 is used with an annular or arcuate side seal groove 21. This side seal groove 21 is formed in a side surface of a rotor 22 which is rotatably received within an engine housing 23 of a rotary piston engine. In the side seal groove 21 an annular or arcuate side seal member 24 is fittedly and slidably received with its axially outer end slidably contacting at numeral 25 with an axially inner side wall of the engine housing 23 to provide oilor gas-tight sealing inbetween. Between the side seal member 24 and the bottom wall 26 of the side seal groove 21 is interposed a generally annular or arcuate biasing element which is in the form of a modified wire spring 27. This wire spring 27 is, as shown, formed with a plurality of alternate projections not only in the axial direction but also in the radial direction with respect to the rotor 22. More specifically, the wire spring .27 is composed of a plurality of spring units each including a base portion 28 of small curvature directly contacting with the bottom wall 26, a top portion 29 of large curvature directly contacting with the side seal member 24, and a supporting portion 31 for connecting the base and top portions 28 and 29. The wire spring 27 further includes an intermediate portion '32 at which the base and supporting portions 28 and 31 merge into each other. As shown in FIGS. 1 and 2,'this intermediate portion 32 has a considerably large curvature not only in the axial direction but also in the radial direction relative to the rotor 22. As a result, the wire spring 27 will break or snap at the intermediate portion 32 due to the torsional shock coming from the sliding movement of the side seal member 24.

Turning now to FIGS. 3, 4 and 6, designated at refer ence numeral 40 is a side seal mechanism according to the present invention, in which like numerals will designate like elements or members. With special reference to FIGS. 3 and 4, the present side seal mechanism 40 has a simplified but improved wire spring 41, which is shown as being generally annular but may be arcuate, if desired. The wire spring 41 is formed with a plurality of alternate projections of sine wave, configuration which are positioned only in the axial direction of the rotor.

Another embodiment of the wire spring is shown at reference numeral 42 in FIG. 5. This wire spring 42 is also formed with a plurality of alternate projections, but these projections are in the form of narrow-necked open loops zigzag but continuously positioned. In this instance, each of the axial projections includes an arcuate portion 43 alternately abutting upon the side seal member 24 and the bottom wall 26 of the side seal groove 21, and two supporting portions 44 roundly extending from the leading ends of the arcuate portion 43 to the neighbouring leading ends of the adjacent arcuate portions 43 for forming the narrow neck of the axial projections. These two supporting portions 44 are formed common to the adjacent axial projections, as shown.

Referring specifically to FIG. 6, a guide groove 45 is formed in the side seal mechanism 40 so as to guide the wire spring 41 or 42 in the axial direction of the rotor 22. This guide groove 45 may be positioned at at least either of the bottom wall 26 of the side seal groove 21 and the bottom wall of the side seal member 24. In FIG. 6, the guide groove 45 is divided into two portions 45a and 45b which are respectively formed in the above two bottom walls. Either of these groove portions 45a and 45b may be dispensed with, if desired, as shown in FIGS. 7 and 8.

Although the number of the guide grooves 45 as shown in these embodiments is one, a plurality of guide grooves 45 may be formed if the wire springs 41 or 42 are arcuate and are several in number.

In connection with the radial location of the guide groove 45, the axially outer end of the side seal member 24 is, as has been shortly discussed, radially outwardly inclined to form the annular contact edge 25, usually, at its radially innermost periphery. With this in mind, the guide groove 45 of FIGS. 6 and 7 are located at the radially outermost position with respect to the side seal groove 21, namely, at the farthest position from the contact edge 25. The guide grooves 45 of FIGS. 8 and 9 are, on the other hand, located at an radially intermediate position with respect to the side seal groove 21. In a more preferred location, the guide groove 45 is located axially just behind the contact edge 25, as shown in FIG. 10. It should be appreciated in this location that the axial biasing force of the wire spring 41 or 42 is exerted on the particular edge 25, thus eliminating the possible rotational force which will rotate the side seal member 24 about the edge 25.

When it is intended to apply the side seal mechanism 40 of the present invention to a side seal groove 46 of FIGS. 11 and 12, then the radially outer end of the side seal member 24 is formed in parallel to the inner wall of the engine housing 23 so as to effect gas-tight sealing inbetween, as shown in FIG. 9.

FIGS. 11 and 12 present a general aspect of the rotary piston engine in which the side seal mechanism of the invention is employed. Since the construction and operation of the rotary piston engine are believed well known in the art, it will be sufficient to point out its main parts or elements by means of reference numerals. Designated at reference numeral 47 is a corner seal member, 48 an apex seal member, 49 an eccentric shaft, 51 a stationary gear, 52 an internal gear, and 53 a main bearing.

As has been described in the above, the present invention should be appreciated in the following points:

1. Since the wire spring can be manufactured by alternately bending a wire material to form a plurality of projections arranged in the same direction, its production cost is materially reduced and its production process is materially simplified; and

2. Since the alternate projections of the wire spring are positioned only in the axial direction with respect to the-rotor, that is, in the direction of thrust application, the wire spring is free from local breakage or snap due to the torsional shock or concentration of stress.

What is claimed is:

1. A side seal mechanism for use in a side seal groove which is formed in a side surface of a rotor rotatably received within an engine housing of a rotary piston engine, comprising:

a side seal member sized and shaped to be slidably received in the side seal groove of said rotor and having its axially outer end slidably contacting an axially inner side wall of said engine housing to provide sealing inbetween;

a guide groove formed in at least one of the bottom wall of said seal groove and said side seal member, said guide groove being located at one of the radial extremities of said side seal groove and being rectangular in shape; and

a wire spring received in said guide groove for biasing said seal member toward said axially inner side wall of said engine housing, said wire spring having a plurality of alternate axial projections lying only in the axial direction with respect to said rotor.

2. The side seal mechanism of claim 1 in which said side seal groove, said side seal member, said guide groove and said wire spring are of annular shape.

3. The side seal mechanism of claim 1 in which said side seal groove, said side seal member, said guide groove and said wire spring are of arcuate shape.

4. The side seal mechanism of claim 1 in which said guide groove is located at the radial outermost position of said side seal groove.

5. The side seal mechanism of claim 1 in which said guide groove is located at the radial innermost position of said side seal groove.

6. A side seal mechanism according to claim 1, wherein said axial projections are in the form of a sine wave.

7. A side seal mechanism according to claim 1, wherein the axially outer end of said side seal member is radially outwardly inclined to form an annular contact edge at its radially innermost periphery.

8. A side seal mechanism according to claim 1, wherein said axial projections are in the form of narrow-necked open loops zigzag but continuously positioned.

9. A side seal mechanism according to claim 8, wherein each of said axial projections includes an arcuate portion lying in the peripheral edge of said coaxial cylinder to abut the bottom of said guide groove, and two supporting portions roundly extending from the leading ends of said arcuate portion to the neighbouring leading ends of the adjacent arcuate portions to form the narrow neck of said each of said axial projections, said two supporting portions being common to the adjacent axial projections to produce the biasing force of said wire spring. 

1. A side seal mechanism for use in a side seal groove which is formed in a side surface of a rotor rotatably received within an engine housing of a rotary piston engine, comprising: a side seal member sized and shaped to be slidably received in the side seal groove of said rotor and having its axially outer end slidably contacting an axially inner side wall of said engine housing to provide sealing inbetween; a guide groove formed in at least one of the bottom wall of said seal groove and said sIde seal member, said guide groove being located at one of the radial extremities of said side seal groove and being rectangular in shape; and a wire spring received in said guide groove for biasing said seal member toward said axially inner side wall of said engine housing, said wire spring having a plurality of alternate axial projections lying only in the axial direction with respect to said rotor.
 2. The side seal mechanism of claim 1 in which said side seal groove, said side seal member, said guide groove and said wire spring are of annular shape.
 3. The side seal mechanism of claim 1 in which said side seal groove, said side seal member, said guide groove and said wire spring are of arcuate shape.
 4. The side seal mechanism of claim 1 in which said guide groove is located at the radial outermost position of said side seal groove.
 5. The side seal mechanism of claim 1 in which said guide groove is located at the radial innermost position of said side seal groove.
 6. A side seal mechanism according to claim 1, wherein said axial projections are in the form of a sine wave.
 7. A side seal mechanism according to claim 1, wherein the axially outer end of said side seal member is radially outwardly inclined to form an annular contact edge at its radially innermost periphery.
 8. A side seal mechanism according to claim 1, wherein said axial projections are in the form of narrow-necked open loops zigzag but continuously positioned.
 9. A side seal mechanism according to claim 8, wherein each of said axial projections includes an arcuate portion lying in the peripheral edge of said coaxial cylinder to abut the bottom of said guide groove, and two supporting portions roundly extending from the leading ends of said arcuate portion to the neighbouring leading ends of the adjacent arcuate portions to form the narrow neck of said each of said axial projections, said two supporting portions being common to the adjacent axial projections to produce the biasing force of said wire spring. 